The present invention relates to a stable aqueous dispersion that forms a water-resistant fast-setting coating when applied to a suitable substrate.
Coatings are generally used to provide a protective barrier for applications such as floors, automobiles, exteriors and interiors of houses, as well as painted roads. Protective coatings for floors, for example, have been known since the mid 1950s. Many of the early coating materials were applied using petroleum- or naphthene-based solvents, and as such were undesirable due to the toxicity and flammability of these solvents.
Water-based synthetic emulsion compositions such as styrene resin emulsions, styrene-acrylate copolymer resin emulsions, and acrylate emulsions, developed in the early 1960s, gradually replaced organic solvent-based compositions. Although the water-based compositions are preferable to organic solvent-based compositions for safety and environmental reasons, coatings prepared from water-based compositions require long drying times. During drying, the coatings are susceptible to a number of events that may produce a defective coating, such as drips, sags and runs. Moreover, until the coating is set, it is vulnerable to contamination by dust or water contact, which may also lead to a marred coating. These effects can be minimized by the use of volatile cosolvents which accelerate the drying process, but the cosolvents reintroduce environmental problems that the water-based systems were designed to address.
In addition to the environmental concerns, one of the challenges that remains is to develop latexes that coalesce at room temperature, without leaving a tacky surface.
In view of the deficiencies in the art, it would be desirable to provide a coating that rapidly becomes resistant to marring, defects, and contamination during drying, using a stable aqueous dispersion that does not require environmentally unacceptable cosolvents or crosslinking curatives.